Collecting Bills

문제 정보


After being retired from ACM-ICPC, Mr. R decided to quit studying computer science to become a farmer. This year, he harvested N cabbages, and the price of one cabbage is K won. R wants to sell all of these cabbages to the Farm Co-Op, but the Farm Co-Op has a rather complicated purchasing policy:

  1. R can split the cabbages into any number of bunches, and sell them separately.
  2. Every time R cells a bunch of cabbages, he has two ways to collect his earnings:
    1. He can get a check: however, checks can be issued only for amounts multiple of 10,000 won, and the remaining money will be thrown away.
    2. He can get the money wired to his bank account: however, the bank will take 10% as transaction fee and round down the remaining money to the nearest won.

So, how much money can Mr.R can get at most by selling all of the cabbages?


The first line of the input file will contain the number of test cases, C. Each line consists of two integers, N and K.

  • C \le 1,000
  • 1 \le N \le 100,000,000
  • 1 \le K \le 100,000,000
  • K \times N \le 2^{31}-1


For each test case, print the maximum amount of money Mr.R can get.

예제 입력

10000 1
9999 1
4 9800
4 2700

예제 출력